Update git submodules

* Update docs/submodules/releng-xci from branch 'master'
  - shabump: Bump SHAs to bring cinder, lxc_hosts, and pip fixes in

    This change brings the fix for
    - cinder haproxy check for ha deployments
    - pip related fixes
    - fixes for lxc_hosts

    Change-Id: I4af64041a4a76c10361456f73577e7c7040edf8a
    Signed-off-by: Fatih Degirmenci <fdegir@gmail.com>

diff --git a/docs/submodules/releng-xci b/docs/submodules/releng-xci
index 455ea6c..56ab31c 160000 (submodule)
--- a/docs/submodules/releng-xci
+++ b/docs/submodules/releng-xci
@@ -1 +1 @@
-Subproject commit 455ea6c732384de5616be9c8c5cb006ae38e6716
+Subproject commit 56ab31c8ae5fe9e4f151fc1de5881c7bb2a09a2f